If $x \circledcirc y = 2x-8$ and $x \bigtriangleup y = x(y-8)$, find $-4 \circledcirc (-3 \bigtriangleup 3)$.
Explanation: We don't need to find $-3 \bigtriangleup 3$ because $x \circledcirc y$ depends only on the left operand. Find $-4 \circledcirc y$ $ -4 \circledcirc y = (2)(-4)-8$ $ \hphantom{-4 \circledcirc y} = -16$.